PCAT Biological Processes – Retrograde Action Potentials
- Jan 03, 2018
- PCAT Question of the Day
Retrograde action potentials are prevented by:
A) leaky K+ diffusion out of the cell
B) absolute refractory period of voltage-gated Na+ channels
C) Na+/K+ ATPase
D) temporal summation of signals from dendrites
Click for Explanation
Retrograde action potentials are prevented by the absolute refractory period of voltage-gated Na+ channels. Since recently opened Na+ channels cannot reopen, the action potential is prevented from traveling in a retrograde fashion. It can only progress anterograde down the axon. If you ever see retrograde conduction mentioned in a neuron question of the MCAT, you should be suspicious of a trap answer.
A) leaky K+ diffusion out of the cell, incorrect, K+ diffusion contributes to the resting potential and has little to do with the action potential.
B) absolute refractory period of voltage-gated Na+ channels, correct.
C) Na+/K+ ATPase, incorrect, The Na+/K+ ATPase helps establish the concentration gradient of Na+ and K+ in the neuron.
D) temporal summation of signals from dendrites, incorrect, Temporal summation of signals from dendrites contributes to action potentials and has nothing to do with anterograde signal conduction.
Search the Blog
Free ConsultationSchedule Now
Free MCAT Practice AccountNeed great MCAT practice?
Get the most representative MCAT practice possible when you sign up for our free MCAT Account, which includes a half-length diagnostic exam and one of our full-length MCAT practice exams.Learn More